Mechanical agitators or stirring devices are commonly employed in hoppers to promote uniform and controlled distribution of particulate matter, such as powder or pellets, within the hopper. Typically, the mechanical agitators continuously stir the contents of the hopper at either a fixed rate or a variable rate to prevent clumping or packing of the particulate matter, thereby promoting the flow of the particulate matter out of the hopper. Other systems use pneumatic vibrators or streams of air to impart vibratory motion to a hopper, thereby deterring the formation of “bridges” or “rat holes” that would impede further movement of the material from the hopper. In addition to these approaches, pulsating air may be used for vibrating a conveyer that transports a particulate material.
Often, particulate delivery systems also include metering mechanisms for measuring and regulating the delivery rate of the particulate materials. Unfortunately, when these systems operate at slow feed rates, the metering mechanisms become more sensitive to vibratory motions. Thus, when used in conjunction with mechanical agitators, the vibrations caused by the mechanical agitators sometimes affect the measurements of the metering mechanisms. In view of this deficiency, a need exists in the industry.